A Certain Natural Gemstone
by SimpleSam
Summary: Academy City is the world's most scientifically advanced city whose research is dedicated towards the esper powers of students. One of these students is a 17-year old boy named Kinuhata Kaiteki, who is obsessed with these powers. However, his life changes when strange events start to happen all around the city like the ones he ran away from so long ago.
1. Prologue The Stongest Gemstone

**Hello lovely reader. This the very first FanFiction that I am posting, a spinoff of the Toaru series and what it would look like if my OC was in it. This is meant to be similar to what Railgun is compared to Index, though the first arc takes place during the poltergeist arc of Railgun, since that is where my OC was meant to be introduced. Well, enough explaining, lets get started. Hope you have a fun time reading.**

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**Prologue:** The Strongest Gemstone

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Academy City. Located within a walled enclave in the Tokyo Metropolitan Employment Area, it is the most scientifically advanced city in the world, with 2.3 million civilians of which 80% are students. The technology in the city is 30 years ahead of the rest of the world, having weaponry far more advanced than any military out there, security robots and powered suits are everywhere, and this is the only city in the world that can produce espers.

"What is an esper?" you might ask. Espers are human beings that have undergone the Power Curriculum Program of the city and have their minds separated from standard reality to create a Personal Reality. They radiate an AIM Diffusion Field which brings their Personal Realities into the standard reality, causing them to have supernatural abilities, which are ranked 0 through 5. With Level 0s having almost to no power whatsoever and Level 5s being strong enough to fight an army alone, of which only 7 are known to exist. There's also a theorized Level 6 which is yet to be seen.

"Okay Gunha, let's try your voice amplification next."

"Alright Kinuhata-kun. You might want to block ears, cause this one's coming right out of my guts!"

Looking at the monitor was a boy named Kinuhata Kaiteki, a 17-year-old third-year high school student with short brown messy hair and blue eyes wearing a white V-neck with a short-sleeved open black jacked over it. Kaiteki is currently at the AIM Analytic Research Center, researching a boy about his age on the other side of the glass. The boy had somewhat windswept black hair and a headband on his forehead wearing a Rising Sun shirt and wearing his uniform like a make-shift cape, Sogiita Gunha, the #7 Level 5 esper in Academy City and the strongest Gemstone. Kaiteki specializes in AIM Diffusion Fields in his own free time, and he researches Gunha because of his unexplainable ability. And since it's summer break, there's no better time then now.

"I don't think that's how screaming works, Gunha. Besides, the room you're in is soundproof, and I hear you through a mic which I can turn off."

"Okay, whenever you're ready!" says Gunha.

"Go for it!" says Kaiteki in a slight impatience.

Gunha deeply inhales and …

"AAAAAAAAAAAAAAAAAAAAAAAAAAAAHHHHHHHHHHHHH!"

He screamed louder than a speaker at concert hall. It seems so loud that a Powered Suit in that same room got blown back towards the wall.

"ALRIGHT GUNHA, THAT'S ENOUGH!" Kaiteki as loud as he could to reach Gunha.

"AAAAAAAAAAAaaaaahhh. So how was that?" Gunha asked.

"WHAT DID YOU SAY?!" screamed Kaiteki in a sarcastic way.

"I SAID-! Oh wait, I get it."

Kaiteki rolled with his eyes.

"I got the results. Now we'll try… let's see… let's try your signature Attack Crash, shall we?" says Kaiteki.

"Okay."

With a few presses on the buttons, Kaiteki activates the Powered Suits that are left standing. The Powered Suits activate and move towards Gunha. Gunha stomps his right feet on the ground, closes his eyes and deeply breaths out. He then takes a karate-like stance, widely opens his eyes and screams: "Amazing Punch!". He then throws his right fist and an explosion occurred. They were not even ten meters away, but the Powered Suits were immediately destroyed.

As Kaiteki watched the monitor he seems to notice something he didn't notice before.

"Oh wow! Gunha, you need to see this!"

Kaiteki opened the door to let Gunha out.

"What is it, Kinuhata-kun?" asked Gunha.

"Look." says Kaiteki.

Gunha looked at the screen and Kaiteki showed his results. On the screen were two different camera footages playing. One that recorded regularly and the other recorded AIM Diffusion Fields.

Kaiteki played the recording of the tests and explained to Gunha what he sees.

"To start off, do you remember why I wanted to research you?" asks Kaiteki.

"It's because even Academy City cannot explain my ability, right?"

"Precisely. It seems like your AIM Diffusion Fields is bending and twisting in an unstable way, even when you're not using your ability. However, when you _do_ use your ability, it stabilizes for a short time, but it somehow behaves differently depending on the power. Look here at your Attack Crash."

Kaiteki pointed his finger towards the two screens whose footage moved in sync with each other and continues to explain.

"It seems as though your AIM creates "something" in front of your fist and the moment you release that "energy" by punching, it creates an explosion that can reach more than 10 meters away."

"Maybe I create an unstable wall of psychokinesis and destroy it with my fist as stimulus, causing an explosive aftereffect." says Gunha.

"That's not how physics work. But to get back to the point, when using your voice amplification, your AIM Diffusion Field acts completely different."

Kaiteki, once again, points his finger at the screens that's now playing the voice amplification clip and explains what he sees.

"When you use your voice amplification, your AIM is more focused at your mouth and throat and seems to strengthen your scream as a result."

Gunha grabs his own chin and thinks.

"Maybe my AIM Diffusion Field acts as some kind of megaphone or something." Gunha tries to explain.

Now Kaiteki grabs his chin. "That may be a possibility, but that still doesn't explain how your Attack Crash works. No wonder that Academy City isn't able to understand it, it just has so many effects that we can't classify it. But I do have a rough theory now, maybe we can't classify it because it isn't just one ability. Gunha," Kaiteki turned his chair around 90° with his arm on his backrest looking directly at Gunha. "I think you're a Dual Skill."

"That's ridiculous. According to scientific research on espers in Academy City, espers are unable to have more than one ability."

The two boys turned around and behind them appeared a scientist in about his mid-forty's with a guard behind him. Kaiteki stood up and walks towards the scientist.

"But that's my point. Gemstones have a much larger AIM Diffusion Field than the ones we create here in Academy City, and most of them have abilities that are not related by science. Besides, there are only about 50 of them around the world, there isn't enough evidence to conclude that they can't."

"That doesn't matter, our espers are the same and work the same. If our espers can't have more than one power at a time, than Gemstones can't either. It's because the brain cannot handle such immense calculations." The scientist shoves his glasses up his face. "Anyway, your time's up. You'll have to come back another day."

"Alright. I'll shut this down, then we're gone." answers Kaiteki.

"Excellent."

After they finish shutting everything down, Gunha and Kaiteki walk outside and talk further about their research and the summer break.

"You really think I have the guts to be a Dual Skill? I mean, it's just like that scientist says, our brains can't handle it." asks Gunha.

"It is just a theory for now, and I don't have a better way describe it. Besides, what he said isn't entirely true. Remember that there is an esper that might control Personal Realities once reaching Level 5." answered Kaiteki.

"Right… Wait… No… Crap, I forgot."

Kaiteki sighed. "Well, no harm in repeating myself. I've heard that there is a certain Level 4 esper who can track AIM Diffusion Fields. It is said that if that person becomes a Level 5, then she can manipulate Personal Realities and is able to give someone Dual Skill."

"That's a lot of guts. Anyway, a bit off topic but would you like to go to the firework display tonight? Or don't you have the guts for it?" asks Gunha.

Kaiteki seems to be a bit surprised by Gunha's offer.

"Seriously?! You, a Level 5, are asking me?! We're not even friends!"

"Hey, I know we only know each other from your research and from school, but it's no reason to not invite you. So, up for it?"

Kaiteki is someone who isn't really that popular and answers a bit awkward.

"S-sure."

"Great, then we'll see each other tonight. Well, I still need to buy some groceries. See ya later!" says Gunha as he leaves.

"See ya".

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**So, what did you think of the prologue? Was it a good start? Was it a bad start? Did I make any mistakes? Let me know what you think, but please keep it polite. Anyway, I hope you enjoyed it nonetheless.  
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	2. Chapter 1 Earthquakes

**Okay, so here we are with chapter 1. This is where it actually begins. So, I have read the (currently only) review that was posted about the prologue. I have read through it again and I realized that it was too short and that I published it too fast, so hopefully this is a bit more entertaining. Anyway, have a fun time reading.  
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**Chapter 1: **Earthquakes

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With Gunha leaving him behind, Kaiteki is waiting for the train to go home on his own. While waiting for the train, Kaiteki seems to think about the research he just did with Gunha.

"Can Gemstones really be Dual Skilled? If so that would explain a lot." he mumbled.

(A Level 5 asking someone like me to have a fun time together? That isn't something you see every day. Then again, he is an odd one.)

Kaiteki gave off a slight smile before the train arrives. When he comes out of the train station, he and everyone around him suddenly start to feel an earthquake. All around him were people panicking and screaming and Kaiteki lost his balance and fell on the ground. The shacking didn't even last 15 seconds before it stopped, and everyone calmed down again.

"Another one? Been happening a lot lately. But what was the deal with that AIM field? Couldn't have been a runaway ability, otherwise it would've stayed in this area."

Kaiteki stood up and continued to walk. He decided to walk through a back alley to get home quicker.

(I started sensing them when I was about 4 years old, strange waves coming from all sorts of different people. I asked my parents what they were, but no one knew what I was talking about. Ever since I started middle school, I've looked into them. And to this day I'm still obsessed with them and esper powers. That is when you know you have a passion.)

Kaiteki had sunken deep into his thoughts until he heard some people behind him. He turned his head around and saw a small group of thugs coming his way.

"Well, what do we have here? A student all on his own in our territory? Can't have that." one of the thugs said while smashing his hands together.

"Can I help you?" Kaiteki responded in a calm way.

"Oh, so you wanna help, huh? Well today is your lucky day boy, you get to give us all your money and expansive items!"

"Damnit… Why is it always about money?" Kaiteki mumbled before turning completely turning around. "Sorry, but I'm out of money. And the only things I can give you are a phone that's out of battery and a high school who is bad at making jokes. So, you're getting nothing."

"Grr! Don't screw with me kid!"

The thug came running towards Kaiteki to punch him in the face. Kaiteki turned to the side and avoided the punch. He then grabbed the thugs arm, put his leg in front of his and pulled the thug further and the thug tumbled on the ground.

"I told you, you're getting nothing!"

"That was a big mistake you made there, bud!"

One of the other thugs behind him held his hand up and created a fireball.

(A Pyrokinesist, eh? I've dealt with those before.) Thought Kaiteki to himself.

"You brought this on yourself, kid!"

The Pyrokinesist then threw the fireball. Kaiteki stretched out his hand in response and caught the fireball no problem.

"What?!"

"You see, Pyrokinesist don't just throw fireballs, they control fire as a whole, even if it is fire they didn't make it themselves. So yeah, the fight-fire-with-fire strategy won't work here, dude." Kaiteki explained.

"Gulp, shit."

With no warning Kaiteki threw the fireball back with even more force then before. While the Pyrokinesist focused on catching the fireball, Kaiteki created fire from his fists using Pyrokinesis to fire himself like a rocket towards the third and last thug behind the Pyrokinesist. Kaiteki punches him in the abdomen and falls to the ground in pain.

"Huh?! Damn you!"

The Pyrokinesist creates another fireball and tries to burn Kaiteki a second time by throwing it into his face. However, Kaiteki saw this coming and waved through the fire to make it go out before he can do anything. Kaiteki then punches him in the face and the thug falls on the ground knocked out.

"You shouldn't rely too much on your power. There's no problem with using it. However, if you don't know how to use it, or worse you encounter someone who knows it better, then you've got a problem."

"You're the one with a problem, brat!"

Out of nowhere, the first thug rushes towards Kaiteki with a knife trying to slash him. Kaiteki didn't have enough time to dodge it and so turns around to block it with his left underarm. Kaiteki did block it. The knife did hit him but wasn't able to cut through the bone. With blood dripping off his arm, Kaiteki let out a loud scream but quickly grabs the thug's arm with his other hand before he had the chance to pull back and proceeds to kick him in the balls. With overwhelming pain, the thug falls to the ground with his hands between his legs.

"That knife is used for stabbing not for cutting, you know…" says Kaiteki.

*VWOOM*

He then heard a strange sound behind him. Kaiteki turned around and saw a girl of about 12-13 years old with two red pigtails wearing a Tokiwadia uniform and a Judgment armband.

"JUDGMENT DESU NO! You're under arrest for- Huh?!"

The girl got confused as she locked around seeing the thugs already beaten up with Kaiteki being the only one left standing.

"Well, Judgment sure took their time…" Kaiteki looks at his arm where a deep wound is located with blood still dripping out. "Hey, are you by any chance a Teleporter? I need to get this patched up fast! The hospital isn't that far from here."

"Right away." The girl put her fingers on her earphone to contact someone else in Judgment. "Uiharu, I need a cleanup team to arrest these thugs, I need to bring an injured to the hospital." The girl hang up and walked towards Kaiteki. "Alright, let's go."

She grabbed Kaiteki by his left arm with the wound on it which hurt Kaiteki a lot.

"Ow! Ow! Ow! Ow! Ow! Ow! Wrong arm! Wrong arm!"

The girl from Judgment immediately let go and grabbed his other arm. "Sorry, my fault." She and Kaiteki then teleported multiple time until they reach the hospital.

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"Thanks for patching up my arm, doc."

"Honestly, didn't you tell me that you wouldn't get into situations like that again?"

"Yeah, sorry about that. But I didn't have much of a choice, I was surrounded and didn't have a weapon."

Following what just happened in the ally, Kaiteki was now sitting in a room with a doctor who had the face of a frog. Kaiteki was sitting next to a table with his black jacked off and his left arm on a table next to him, with the wound clearly visible.

"Well, looks like you were lucky, sort of. The bone has a small scratch on it, and your sinews aren't badly damaged either."

"So I won't be able to use my arm for a while?"

"Yes and no. You'll be able to use it for everyday things and it'll only feel a little bit stiff, but you have to be careful with it, or else you'll break your arm. So no fighting for a while or else it won't heal." The frog-faced doctor then applied synthetic skin at the place of the wound as the final step. "So, that should do it. As long as you don't overdo it, nothing will go wrong." The wound may have closed, but you could still clearly see the synthetic skin stand out from his actual skin. "But knowing you that won't be the case, so I need you to come back tomorrow evening. I'm very busy tomorrow so I'll make an exception and stay a little longer after work for you."

The frog faced doctor handed Kaiteki a small note with the time of his appointment. Kaiteki held his arm in his right hand and tried to close and open his left hand. Like the doctor said, it was a bit stiff but worked just fine.

Kaiteki looked up, accepted the note. "Alright." he said with a bored tone as he walked towards the coat rack with his jacked. "Well, I gotta get going. I've got my own plans for a change tonight."

The frog-faced doctor gave a serious and concerned look. "Hopefully nothing like this again."

"No, it's nothing like that. I'm going to that firework display and I want to have eaten before that."

"Oh?" The doctor seems a bit surprised by his answer. "What made you decide that? Did your friend invite you?"

Kaiteki now had his jacked back on. "Well… I wouldn't call him a friend necessarily, but you can't really turn down an invitation from a Level 5, right?"

"I'm only saying that you shouldn't go if you don't want to."

"It's alright. I'm going anyway. Then I'm at least doing something else than sitting behind a monitor the entire day." Opening the door, Kaiteki looked back to say goodbye once again. "See you tomorrow."

"Be carefull out there!" The frog-faced doctor said when the door closed.

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Before the firework display starts, Kaiteki is walking around the stalls of the festival looking for Gunha while trying to find anything interesting.

"Oi! Kinuhata-kun!" And there he was. He came running at Kaiteki faster than a bullet and stopped right in front of him. "So, you did have the guts come after all. I was looking all over the place for you."

"Of course I came. I can't really turn down a Level 5, right?"

It took a moment for Gunha to notice that Kaiteki's arm had synthetic skin on it.

"Hey Kinuhata-kun, what's the deal with that birthmark? I didn't notice you had that before."

"Oh, this?. It's not a birthmark, it's synthetic skin. On my way home after you left, I got attacked by a few thugs and injured my arm."

"Really?" Gunha bumped his fists together and got a little mad at himself. "Grr. If only I had known that, I could've helped you with my guts."

"Hey, don't blame yourself. In the end I'm alright and had enough guts to beat them myself."

Gunha let out a sigh. "Well, I've seen some stalls around here that seem pretty fun. Let's go."

They walk around the stalls trying to find interesting things. Kaiteki was more of the strategical games whereas Gunha play more games that required strength. Some of the stalls they visited were quoits(1), High striker (which Gunha easily won) and buying some food every now and again. At the end of the stalls, there was stall that sold masks for the festival. Kaiteki points at a unicorn mask.

"Hey Gunha, maybe you'd like a mask like that." Kaiteki chuckles a bit.

"Shut up!"

"Alright, alright." Kaiteki notices some weird trucks standing on the parking lots. He points at those trucks and Gunha looked at them. "Hey Gunha, any idea what those trucks are for?"

"I don't know, you're the smart guy here."

Kaiteki then sees a group of 5 girls wearing yukata, one of which just walked away, close to those trucks seemingly to get away from the noise for a bit.

"Hey, I recognize that girl."

Gunha now looked towards them as well. "You do?"

"Yeah. The one with those red pigtails is from Judgment. She helped me get to the hospital earlier today."

Kaiteki decides to walk up to them, with Gunha following him. As they walk up to the girls, the one with the red pigtails notices the two guys walking up to them.

"Oh hey, there you are again. How is that arm of yours?"

"Better I expected. My sinews are damaged a bit and the bone has a scratch on it, but I should be able to use it just fine as long as I don't overdo it. Thank you for your help and concern." Kaiteki made a small bow.

"No problem. It's our job as members of Judgment to help civilians."

"Now that you mention it, I wanted to ask you what those trucks are all about."

"That's MAR—the Multi Active Rescue team's trailers. They're probably here as a countermeasure to the poltergeisting."

Another girl in the group with flowers in her hair joined the conversation, followed by one with long black hair.

"Poltergeisting?! So those rumors _are_ real?!"

"Poltergeisting? Come on, those are just rumors. No way they can be true." said Kaiteki

"It's not the entire story. They're an effect of something called RSPK Syndrome, that—"

"RSPK Syndrome?! Oh shit!"

Before the pigtailed girl from Judgment could finish her sentence, Kaiteki cut her off.

"Um… What's that exactly, Kinuhata-kun?" asks Gunha.

"Recurrent Spontaneous PsychoKinesis Syndrome. It happens when an esper loses control over their ability, causing a subconscious and uncontrollable outburst of power. It can be caused if the esper has a trauma or mental stress. Normally that would only occur in the form of a runaway ability, but for something that feels like an earthquake requires the synchronization of multiple esper's AIM Diffusion Fields."

"Crap! That's even worse than I thought. That'll probably take a lot of guts to stop. If that were to occur…"

"Then it's a good thing MAR and Judgment are here in case that occurs."

"Let's just hope it doesn't happen. So, I hope this clears up the confusion?" said the pig-tailed Judgment member.

"Yeah, thanks a lot. Enjoy the fireworks." Kaiteki and Gunha than walk off back into the crowd.

"You too!" the pig-tailed girl screamed back.

Kaiteki and Gunha now are strolling around the stalls again but both of them seems to be very worried now.

"That RSPK Syndrome seems quite dangers, eh? It's a good thing that I came here then."

Kaiteki nodded. "Like that girl from Judgment said, let's just hope it doesn't happen."

Then suddenly, the boys see a bright light followed by a bang. The two looked up. The fireworks started.

"Wow!" Kaiteki looks at Gunha who looks at the firework. "You know what Gunha, I'm glad you invited me. It's not often that people ask me to do something with them, not to mention that I would've missed this." Kaiteki then suddenly gets a headache. He grabs his head and gets down to the ground.

"Kinuhata-kun?! Are you alright?!"

Kaiteki looks up to the hill behind them. "Somethings happening up there. Is that an AIM field…? Shit!"

Suddenly Kaiteki turns around and his eyes begin to glow a bright green color and without warning runs off at twice the speed of sound. Gunha tries to go after him but it's too late, a poltergeist happening. The moment he arrives at the upper-area, Kaiteki jumps over the fence that prevents people from falling of the hill when he feels the poltergeist happening. He then sees that girl from earlier with flowers in her hair lying on the floor covering her friend when they're almost being crushed by a light post. Kaiteki runs at them, again at twice the speed of sound, to push the two out of the way before they're crushed.

"LOOK OUT!"

Kaiteki pushed the two girls out of the way right before they're hit. Kaiteki, now covering the two girls, jumps up from shock.

"Crap, my arm! I shouldn't have used my ar- huh?!" Kaiteki looked at his left arm only to find out that the synthetic skin over his wound is much smaller now. (What? Why is the- Oh it's because of him, isn't it?) Kaiteki now took a good look at the girls. "Are you okay?"

"Yes, thank you!" says the one with the flowers while nodding.

The other girl had short dark hair with a few strands of them tied together on the left side of her head. Instead of thanking him, she just held her pendant with her eyes closed.

"Where… are you?"

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**(1) I don't know if this is the correct word for it (since I'm not English) but the game I meant is the one where you throw open rings at a stake.**

**So that was chapter 1. I hope i did better with this one than with the prologue, because that one was just boring. I'm having a lot of fun making this fanfiction and I'm already a bit further into the fanfiction than what I've already posted. It is gonna take a while before chapter 2 though, as I'm very busy with school and exams at the moment, but I just wanted to get this done so I could "fix my mistake". Also, I tried to find a good way to translate "Judgment desu no!", but I couldn't find a good translation for that since there are so many with different ways to say it, so I just kept it like that. Anyway, hope you enjoyed reading and keep giving me feedback. Until next time, bye.**


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